Influence of Environmental Decomposition of Logging Residues on Fuel Properties

Abstract

All biorefining processes for lignocellulosic biomass, whether ethanol production using fermentation, bio-oil, syngas, or Fisher-Tropsch liquid production using thermochemical conversion, rely on the physical and chemical properties of the feedstock, which may change significantly when wood residues are left on the forest floor for long periods after timber harvesting. If these changes do not occur, then logging residues need not be collected along with the main timber products, which would affect the supply chain logistics for bulk storage and preprocessing requirements. However, if changes in wood composition do occur, then a logical harvesting time frame must be established for the logging residues. This article presents a study on the effects of environmental decomposition of forest residues to be used for biorefining applications and a determination of a logistical harvesting timeframe. Samples of forest logging residues of red maple and yellow poplar were collected from the West Virginia University Research Forest at a site where timber harvesting operations were conducted in 2010 and 2005. Selected fuel-related properties were measured on the collected samples and include moisture content, particle size, bulk density, true grind density, porosity, calorific value, proximate analysis (moisture, volatile matter, fixed carbon, and ash), ultimate analysis (carbon, hydrogen, nitrogen, sulfur, and oxygen), and thermogravimetric analysis (TGA). TGA-FTIR data were analyzed to assess the influence of environmental decay on the thermal degradation behavior of the samples. Differences in the TGA results with collection delays for each wood species were explained using data from the proximate, ultimate, and chemical composition analyses. The results showed a decrease in moisture content and no change in calorific value.